Non-spill vent plug for storage batteries



June 1, 1937. J. L. WOODBRIDGE 2,032,606

NONSPILL VENT PLUG FOR STORAGE BATTERIES Filed April 2, 1936 \Ir Iii//VVE/V0/? Jafse v/r [6&7 Mad/512376 M6540! Cay/irks 5W Patented June1., 1937 UNITED STATES NON-SPILL VENT PLUG FOR STORAGE BATTERIES JosephLester Woodbridge, Philadelphia, Pa., assignor to The Electric StorageBattery Company, Philadelphia, Pa., a corporation of New JerseyApplication April 2, 1936, Serial No. 72,277

4 Claims.

The present invention is an improvement on or applicable to the ventplug described in my application Serial No. 19,638, of May 3, 1935. Inthe operation of the vent plug disclosed in said application sometimesliquid collecting in the interior of the plug above the diaphragm valvedoes not drain back into the cell when the latter is restored toits'vertical position.

It is the principal object of the present invention to overcome thatdefect or disadvantage. l have observed that the failure to drainproperly, above referred to, occurs when slight gaseous pressuredevelops in the call, and the present invention consists in theprovision of means foi establishing a capillary path extending below thediaphragm valve from a point in proximity with a perforation, whichoperates to oppose effect of such pressure and to ensure properdrainage.

The invention also comprises the improvements to be presently describedand finally claimed.

In the following description reference will be made to the accompanyingdrawing forming part hereof and in which,

Figure 1 is a view partly in central section and partly in elevationdrawn to a very much enlarged scale of a vent plug embodying features ofthe invention.

Figure 2 is a plan view looking upward in Figure 1 with parts omitted;and

Figure 3 is a view similar to Figure 1 illustrating a modification.

Referring to the drawing, I indicates the cover of a storage batterycell and it is known that pressure above atmosphere develops in thecell. The'vent plug 2 is internally sub-divided by an annular partition3 providing an axially disposed vent passage 4 and also providing on itsinner face a diaphragm valve seat 5. The plug is equipped with aweight-operatedelastic diaphragm' 6 as of rubber stressed toward theseat and provided with an imperforate center portion 8 for sealing thepassage 4 when the device is tilted. The diaphragm is also provided withperforated portions 9 for affording access to the passage 4 for ventingthe cell and from the passage for drainage when the device is upright.Back pressure in the cell operates to oppose drainage. capillary pathextending below the diaphragm from a point in proximity with aperforaton, and these means operate to obviate the effect of the backpressure. As shown in Figures, 1 and 2 these means comprise slots l0provided in the wall of the vent passage and they extend do nward frompoints near perforations 9 in the There are means for establishing adiaphragm. In Figure 3 there is shown a modifled form of capillary pathand it consists of a fibrous wick ll whose upper end is fastened byinsertion into the annular partition and whose lower end extendsdownward by one of the perforations 9 in the diaphragm. The wick liesclose to the wall of the passage 4.

As to the mode of operation it may be suggested that the defectivedrainage in the device of the prior application was due to the uniform10 distribution of pressure over all of the surfaces of the liquidentrained in the passage around the plunger l2 and between the diaphragmand the valve seat when the cap is depressed by the weight of the balll3.- It is to be understood that 15 back pressure is assumed to exist inthe cell and beneath the cover I. Drainage of this liquid is effectedagainst. such gaseous pressure by unbalancing the pressure and thecapillary path described extending from some point on the surface of theentrained liquid above the diaphragm operates to produce that result sothat drainage is effected.

It will be noted that the slots extend to an internal shoulder I locatedin close proximity with the soft rubber diaphragm when the latter isdepressed by the weight of the ball. It will also be noted that the ventpassage 4 is noncapillary while the capillary path indicated by theslots III in Figure 1 or the wick i l in Figure 3 is in parallelrelation with the non-capillary vent passage 4 below the diaphragm 8.

I claim:

1. A vent plug of the type recited having an axially disposed ventpassage through it and equipped with a weight-operated resilientdiaphragm provided with an imperforate portion for sealing the outlet ofthe passage when the device is in tilted position and with a perforatedportion for affording access to the passage when 40 the device is inupright position, a non-capillary passage below and communicating withthe perforated portion of the diaphragm, and means for establishing. acapillary path paralleling said non-capillary passage and extendingbelow said 5 diaphragm from a point in proximity with a perforation inthe diaphragm.

2. For sortage battery cells a non-spill vent plug having an annularpartition sub-dividing its interior and providing an axially disposedvent passage and also providing on its inner face a diaphragm valveseat, said plug equipped with a weight-operated elastic diaphragmstressed toward said seat and provided with an imperforate centerportion for sealing said passage when the device is tilted and with aperforated portion for affording access to the passage for venting thecell and from the passage for drainage when the device is upright, saidplug having walls defining a non-capillary passage below said diaphragm,back pressure in the cell operating to oppose drainage, and a slot inthe wall of said lower passage for establishing a capillary pathextending below the diaphragm from a point in proximity with aperforation thereof and adapted to obviate the efiect of the backpressure.

3. In combination in a non-spill vent plug for a battery cell in whichgas is evolved, walls defining a hollow chamber vented into theatmosphere, a non-capillary passage from the chamber adapted tocommunicate with the interior of the cell, a valve intermediate saidpassage, adapted to close said passage upon tilting of the cell and acapillary path adjacent said passage and said valve for connecting thechamber with the interior of the cell when said valve is open, saidcapillary path adapted to drain liquid from the chamber into the cellagainst the flow of gas from the cell into the chamber.

4. In combination in a non-spill vent plug for a battery cell in whichgas is evolved and develops pressure, a valve normally open to providefor the escape of gas when the cell is in upright position but adaptedto be closed by the tilting of the cell, walls defining a confined spaceabove the valve, vented into the atmosphere, wherein liquid may betrapped, and a capillary and a non-capillary path in parallel relationbetween the valve and the interior of the cell whereof the latterprovides for the escape of gas and the former provides for drainage ofthe trapped liquid against gas pressure.

